NFS: Fix an Oops in NFS unmount

Ensure that the dummy 'root dentry' is invisible to d_find_alias(). If not,
then it may be spliced into the tree if a parent directory from the same
filesystem gets mounted at a later time.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2007-12-12 11:12:15 -05:00
parent a5576cfa5c
commit a10db50a4a
1 changed files with 11 additions and 0 deletions

View File

@ -57,6 +57,17 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i
}
/* Circumvent igrab(): we know the inode is not being freed */
atomic_inc(&inode->i_count);
/*
* Ensure that this dentry is invisible to d_find_alias().
* Otherwise, it may be spliced into the tree by
* d_materialise_unique if a parent directory from the same
* filesystem gets mounted at a later time.
* This again causes shrink_dcache_for_umount_subtree() to
* Oops, since the test for IS_ROOT() will fail.
*/
spin_lock(&dcache_lock);
list_del_init(&sb->s_root->d_alias);
spin_unlock(&dcache_lock);
}
return 0;
}